A family from Alabama believes they had a frightening encounter with Navy Yard shooter Aaron Alexis last month while flying from a Virginia airport when an enraged man accused them of laughing at him.

The stranger delivered a rant filled with profanities and at least one racial epithet because he thought the family, including a wheelchair-bound woman, was laughing at him in the Norfolk airport on Aug. 4.

"It was a disturbing type of behavior," Glynda Boyd told ABC News. "I felt fear. A sense of fear because it was off. He looked like he was puzzled, something was wrong. You could tell his behavior, something wasn't right with him mentally."

Boyd said the scary confrontation, first reported by FoxNews.com, was triggered by an inside joke at Norfolk Airport among the family that included her brother and aunt. Her wheelchair-bound aunt Rosalind Baugh laughed loudly, which drew the attention of the man she is certain was Alexis, she said.

Alexis angrily approached the group, demanding to know why they were laughing at him. Things quickly escalated with Alexis screaming profanities and motioning at his side as though he were carrying a weapon.

Boyd said Alexis screamed numerous curses at the family standing no more than two feet from them and used the N-word. Both the family and Alexis are black. Boyd said when she saw Alexis' picture on TV following the shooting, she screamed.

"I turned on the television and I saw his face on the news and I just screamed, 'Oh my God, that's him, oh my God,'" Boyd said. "And I just started screaming and I did not go to sleep. Did not sleep, couldn't because it just kept playing back in my mind, my encounter with him and my family."

Three days after the incident, Alexis filed a police report in Rhode Island, stating he had argued with a person at an airport in Virginia and that individual "sent three people to follow him" and that they were harassing him with a microwave machine.

Alexis, a 34-year-old former Navy reservist, opened fire Monday at the Navy Yard in Washington, D.C., killing 12 people and injuring eight others. Alexis' past is filled with documented anger issues, outbursts and violence long before he walked into the Navy Yard complex.

A federal law enforcement official confirmed to ABC News today that investigators have determined Alexis was at the airport in Norfolk on Aug. 4 and was involved in a verbal altercation with another passenger in the terminal.

The official could not say for certain that the incident involved the family ABC News spoke to but said their story rings true.

The family never saw Alexis before he walked up to them and accused Boyd's aunt of laughing at him.

"'Who is that lady? Why she keep looking at me,'" Alexis asked, according to Boyd.

When Boyd explained to Alexis that she was not laughing at him, he remained standing there "puzzled" but calm.

"When he walked away the first time, they automatically started saying, 'wow he's weird,'" Boyd said of passengers' reaction to the confrontation in the terminal. "That's when they said things like he acted like he was snorting bath salts."

Alexis, Boyd said, returned five minutes later and accused Baugh of laughing at him once more. That's when Boyd's brother confronted Alexis and told him he was out of line. Boyd said Alexis' demeanor changed and he became agitated as her brother defended their aunt.

"They ended up having words back and forth because his behavior was inappropriate," Boyd said. "This young man started to use profanity and cursing and he was out of control."

Boyd said he kept reaching for his side as if he had something on him during the heated confrontation. Boyd said she thought Alexis was trying to indicate he had a weapon, but she felt confident that wasn't the case because she figured he had to go through airport security. Boyd moved her family, but Alexis continued to curse at the family and use the N-word.

"That's the only thing I recall him saying, but he was saying other things. But that just rang out in my mind. I could hear him saying that," she said.

Three to four security officers arrived on the scene and spoke to Alexis and told him if he didn't stop he wouldn't be able to fly, according to Boyd.

"The people around just had conversations as if maybe he was on some type of drug, or maybe he needed medicine or forgot to take his medicine," Boyd said.

Boyd said the situation came to an end when security arrived and Alexis calmly sat near his departure gate.